Author + information
- Luis C.L. Correia, MD, PhD⁎ ( and )
- Anis Rassi Jr, MD, PhD
- ↵⁎Medical School of Bahia, Av. Princesa Leopoldina, 19/402, 40.150-080 Salvador, BA, Brazil
In a population-based cohort of 4,129 subjects without overt coronary artery disease at baseline, Erbel et al. (1) demonstrated that coronary artery calcium (CAC) scoring provides a significant improvement in discrimination and a high level of correct reclassification when applied to persons initially identified by the Framingham criteria as having an intermediate risk for coronary events. The investigators concluded that “limiting CAC scoring to intermediate-risk subjects can contribute to reducing the number of coronary events in the general population.” Because prediction does not necessarily lead to prevention, we should scrutinize the level of scientific evidence on the ability of CAC scoring to improve health outcomes.
To reduce disease-specific morbidity or mortality, the process of reclassification should be able to select subjects to more intensive treatment of modifiable risk factors. According to results derived from the investigators' Table 3 (1), 77% of correct reclassification in subjects with 10% to 20% risk was confined to down-classification of those without events. Obviously, this type of reclassification does not induce physicians to enhance preventive strategies. In contrast, there is no scientific evidence that it is safe to downgrade preventive care on the basis of a low CAC score. Thus, 77% of correct reclassification obtained by CAC scoring should have no impact on clinical management and outcomes.
And what about up-classification of those with events, which took place in the remaining 23% of correct reclassification (1)? Should it modify preventive strategies? Regarding statin therapy, a reduction in coronary events has been recently demonstrated by aggressive lipid lowering in intermediate-risk subjects with normal low-density lipoprotein cholesterol levels (2). Thus, it is unlikely that CAC scoring will modify the recommendations for statin therapy in this population. Second, the indication for initiating drug therapy in patients with hypertension and target blood pressure values should not differ between intermediate-risk and high-risk subjects (3). Finally, should aspirin be used in subjects reclassified to high risk? The magnitude of absolute risk reduction of cardiovascular events by aspirin in primary prevention is small, and the risk/benefit ratio does not justify its use in most subjects (4). Recently, the long-term beneficial effect of aspirin in patients with diabetes has been questioned in several randomized clinical trials (5), suggesting that aspirin is justified only for very high-risk patients, mostly in the secondary prevention setting. In addition, aspirin did not prove beneficial in a clinical trial focused on asymptomatic subjects with subclinical atherosclerosis assessed by ankle-brachial index (6). Finally, lifestyle measures, such as smoking cessation, weight control, and exercise, are universally recommended, regardless of risk profile.
Therefore, the utility of reclassifying intermediate-risk subjects may be a questionable paradigm, and before implementing such a strategy, the efficacy of using CAC scoring should be tested by appropriate clinical trials comparing the incidence of cardiovascular events between subjects randomized to CAC scoring and those randomized to no CAC scoring.
- American College of Cardiology Foundation
- Erbel R.,
- Mohlenkamp S.,
- Moebus S.,
- et al.
- Garg J.,
- Messerli A.W.,
- Bakris G.L.
- De Berardis G.,
- Sacco M.,
- Strippoli G.F.,
- et al.